Lawyers for Gov. Rick Perry challenged his indictment in legal filings Monday, calling the charges unconstitutional and asking the courts to throw them out.

Perry was indicted this month, accused of coercing a public servant and abusing his official capacity of governor when he threatened to veto $7.5 million in state funds to the public corruption unit of the Travis County District Attorney's office if District Attorney Rosemary Lehmberg refused to step down after her April 2013 drunken driving arrest.

“Continued prosecution of Governor Perry on the current indictment is unprecedented, insupportable and simply impermissible,” the attorneys wrote in their brief. “This court should not hesitate to dismiss both counts of the indictment and bar the prosecution, immediately if not sooner.”

In the brief signed by David Botsford, one of a half-dozen lawyers hired by the governor, Perry’s team contends the indictments violate constitutional provisions for the separation of powers and protecting free speech, and the brief said that the charges are vague, overbroad and improperly applied.

The governor’s defense team promised a challenge last week; the court said at that time that the prosecutor will have a week to respond.